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Optical transitions of a pristine (8,0) single-walled carbon nanotube (SWCNT) and the (8,0) SWCNT containing three types of defects were calculated based on electronic structures obtained using the...

The theoretical study of hydrazine in the presence of moisture doped single-walled carbon nanotube (SWCNT) where the donor state (DS) occurred in the electronic band structure, which has previously been reported. Herein, We reveal that the density functional theory (DFT) studies of pure hydrazine formed the hydrogen bond network (HBN) on SWCNT, leading to the n-type behavior. DFT approaches including van der Waals corrections were carried out to understand the specific configuration of hydrazine, which causes the occurrence of the DS. The electronic band structures are classified according to three groups. First, is the impurity state below the maximum valence state (ISBMVS). Second, is the impurity state close to (below) the maximum valence state (ISCMVS), and third, is the DS. The reduced density gradient (RDG) approach and the Bader charge analysis were used to address a specific hydrazine molecule, which caused the DS to occur. The NMR chemical shifts and UV–Vis spectroscopic parameters can be used for comparison with experiments to confirm the theoretical models.

The samples of Cu1−xPtxFeO2 (0 ≤ x ≤ 0.05) delafossite have been synthesized by solid-state reaction method to investigate their optical and electrical properties. The properties of electrical resistivity and Seebeck coefficient were measured in the high temperature ranging from 300 to 960 K, and the Hall effect and the optical properties were measured at room temperature. The obtained results of Seebeck showed the samples are p-type conductor. The optical properties at room temperature exhibited the samples are transparent visible light material with optical direct gap 3.45 eV. The low electrical resistivity, hole mobility and carrier density at room temperature displayed value ranging from 0.29 to 0.08 Ω cm, 1.8 to 8.6 cm2/V s and 1.56 × 1018 to 4.04 × 1019 cm−3, respectively. The temperature range for transparent visible light is below 820 K because the direct energy gap contains value above 3.1 eV. Consequently, the Cu1−xPtxFeO2 delafossite enhance performance for materials of p-type transparent conducting oxide (TCO) with low electrical resistivity.

The samples of Cu1−xPtxFeO2 (0 ≤ x ≤ 0.05) delafossite were synthesized by solid state reaction method for studying thermoelectric properties. The properties of Seebeck coefficient, electrical conductivity and thermal conductivity were measured in the high temperature ranging from 300 to 960 K. The results of Seebeck coefficient, electrical conductivity and power factor were increased with increasing Pt substitution and temperature. The thermal conductivity was decreased from 5.8 to 3.5 W/mK with increasing the temperature from 300 to 960 K. An important results, the highest value of power factor and ZT is 2.0 × 10−4 W/mK2 and 0.05, respectively, for x = 0.05 at 960 K.

The title compounds are prepared by solid state reaction of stoichiometric mixtures of CuO, Fe2O3, and PtCl2 (1050 °C, 15—25 h) and characterized by powder XRD, SEM, and thermoelectric measurements between 300 and 960 K.